A Child's View

What children look at and what they don't—in other words, what captures their attention—is strongly influenced by genetics, found researchers at Emory's School of Medicine, Marcus Autism Center, Children's Healthcare of Atlanta, and Washington University School of Medicine.

"How a child looks at the world is how she learns about the world," says Warren Jones, Nien Distinguished Chair in Autism at Emory and senior author of the study, which was featured in Nature. "Each eye movement, happening every half-second, shapes brain development. So you can imagine these effects rippling forward, creating the way a child sees and understands her world." The study examined 338 children—including 82 identical twins (same genetics) and 84 non-identical twins (shared genetics, as with any sibling). Researchers used eye-tracking technology to measure each child's eye movement while they watched videos of childhood scenes.

Identical twins were nearly identical in the way they watched the videos. For non-identical twins, that match fell to about 10%. Identical twins were also more likely to move their eyes at the same time, in the same direction, toward the same location and the same content, mirroring one another's behavior to within 17 milliseconds. When the twins were tested again more than a year later, identical twins remained almost perfectly matched, but non-identical twins were slightly less matched than before.

Earlier research by members of the team showed that babies who look progressively less at people's eyes are more likely to have autism.

With these new results in twins, the team has found a specific behavior highly influenced by genetics and directly linked to autism risk.